In the art of shingle manufacture, it has been known that laminated shingles may be prepared using separate layers. Each layer is constructed, generally of a bituminous coated web, with granules applied to an upper surface thereof.
The two shingle layers are then laminated together, by application of an adhesive, generally a bituminous material, to the back of the secondary layer, which is then applied over the base layer, whereby the adhesive secures the layers together, sandwiching granules from the top of the base layer therebetween. Examples of laminated shingles include those disclosed in U.S. Pat. Nos. 5,181,361 and 5,287,669, for example.
One prior art process for producing a laminated shingle is disclosed in FIG. 1 hereof, which will hereinafter be discussed in greater detail.